EP2343793B1 - Connection module for direct current motors - Google Patents

Description

The present invention relates to a direct current motor with a motor housing and at least one connection module which can be attached to the motor housing and which has fastening options for fastening the direct current motor to an installation point, the motor housing having a front centering elevation which interacts with a centering recess on the connection module.

In small DC motors that have been customary up to now, the motor housing often consists of one part that combines the functions of external yoke for the field of the permanent magnet and connection flange with a defined drilling pattern. Usually the motor housing is turned from the solid. If the precision requirements are somewhat lower, it is also known to manufacture the motor housing using deep-drawing technology and to rework the connection threads.

Furthermore, designs for motor housings are known in which the external yoke for the field of the permanent magnet and the connection flange with the defined drilling pattern are separate parts that are connected to one another in a fixed angular position by pressing, welding, screwing, pinning or similar types of connection.

All of these motor housings have a fixed construction. If a customer needs a different drilling pattern to attach the motor to the intended location, this means that the motor has to be rebuilt from scratch, as either the motor housing has to be adapted accordingly or the connection flange has to be adapted to the customer's specification.

In order to implement such modifications, it is therefore already known to attach an adapter plate to the end face of the motor housing which has the drilling pattern desired by the customer. This enables faster delivery, as an already finished motor can be obtained to which only the corresponding adapter plate has to be attached. Disadvantages here are the additional assembly effort for fastening the adapter plate, the additional overall length due to the adapter plate and the costs for the additional adapter plate.

U.S. 4,227,101 shows a stepper motor with an adapter ring. The adapter ring is used to fasten the stepper motor at an installation point and has a connection hole pattern for this purpose. The motor housing of the stepper motor has a centering projection and threaded holes for connection to the adapter ring on its front side. The adapter ring is with provided a central bore and has three arcuate elongated holes on its circumference. The adapter ring is pushed onto the motor housing so that the centering projection of the motor housing protrudes through the bore of the adapter ring. Screws are attached to the curved elongated holes of the adapter ring, which are inserted into the threaded holes of the motor housing and tightened slightly. In this assembly position, the adapter ring is loosely attached to the motor housing by means of the screws. In the assembly position, the adapter ring can still be turned, as long as the elongated holes permit. The adapter ring can therefore be twisted to a limited extent. This allows the motor shaft to be brought into the desired position in relation to the connection hole pattern in the adapter ring. Once this has been done, the screws in the elongated holes are tightened so that the adapter ring is firmly connected to the motor housing in the assembled state. Since the adapter ring can only be rotated to a limited extent, only certain positions of the connection hole pattern can be set.

Out DE 102005030217 A1 an electric motor with an adapter element is known. The adapter ring encloses an outer jacket surface of the electric motor housing. For a form fit between the motor housing and the adapter, radial recesses are made in the outer surface of the electric motor housing, into which the fastening webs of the adapter protrude radially inward. In the circumferential direction, areas of the electric motor housing remain undeformed between the radial recesses, so that they form a stop for the fastening webs in the circumferential direction.

Out DE 20302174 U1 an electric motor with a connection module pressed into the housing of the electric motor is known. The connection module is located inside the housing and carries the housing cover, which is closed by a cover plate.

In DE 102004011666 A1 describes a linear actuator which comprises a stepper motor and a guide housing attached to it. The housing of the stepper motor comprises a fastening flange which engages in a so-called centering recess of the guide housing. The guide housing is fastened to the housing of the stepping motor by means of fastening screws which are inserted through drill holes in the guide housing and screwed into blind holes in the housing.

The DE 36 35 987 A1 shows an electrical machine with a cylindrical housing, on the end faces of which end shields are attached. For this purpose, the edges of the cylindrical housing are designed as centering bushes, the edges of the end shields as centering jackets which are fitted into the centering bushes of the housing without play.

The EP 09 15 555 A1 discloses a housing for a quiet electric motor, on the outer surface of which a fastening flange is attached.

In the U.S. 4,076,197 an engine mounting system is disclosed in which mounting arms are attached to the outer surface of a cylindrical engine housing. The mounting arms can be attached directly to the motor housing or to a mounting bracket that is attached to the motor housing.

DE 690 25 317 C2 describes a small electric motor with a mounting flange. The small electric motor can be attached to the desired installation location with the mounting flange. The mounting flange has a cup-shaped section with which it is slipped onto the peripheral surface of the motor housing of the small electric motor. In this position, the mounting flange and the motor housing are glued together. The disadvantage here is that the small electric motor requires a relatively large amount of space.

Another disadvantage is that in the case of brushed DC motors, the brush cover is usually rotated relative to the stator with the permanent magnets mounted in the stator in order to set the commutation. The angular position of the electrical connections in relation to the drilling pattern of the connection flange is therefore not defined. There can be differences of up to ± 25 ° from motor to motor. This can cause problems, especially in applications with tight installation space or when several motors have to be installed very close to one another.

It is therefore the object of the present invention to provide a direct current motor which avoids the disadvantages of the solutions known from the prior art and in particular is compact, can be flexibly adapted to customer requirements and can be easily installed even with little installation space.

For this purpose, the invention provides according to claim 1 that the connection module can be freely rotated into any position in an installed state on the motor housing and is connected to the motor housing in a non-rotatable manner in this desired position, with a bearing for the motor shaft of the DC motor on the end face of the motor housing is arranged, at least partially protrudes over the end face of the motor housing and forms the centering elevation, wherein the connection module is pushed onto the bearing and that the motor housing has a motor housing base in which a shoulder is formed and the connection module has a protruding rib which in the paragraph comes to rest.

The connection module, on which the fastening options for fastening the motor at the intended installation point are provided, is attached to the end face of the motor housing. The connection module thus has the function of a connection flange. The connection module is plugged onto the end face of the direct current motor so that the centering elevation or the centering recess of the connection module engages in the centering recess of the direct current motor or surrounds the centering elevation of the direct current motor. Since the connection module can be rotated freely in the assembled state, it can be rotated into any position. In this position, the connection module is firmly connected to the motor housing, so that it is attached to the motor housing so that it cannot rotate when installed. The connection module can therefore be attached to the motor housing in any position. There are no connection holes on the front of the motor housing. The wall thickness of the end face of the housing can therefore be relatively thin, so that a housing with a minimal length can be realized. This makes the DC motor compact and inexpensive. There are no variants with regard to the connection geometry to be taken into account on the assembly line for the DC motor. The assembly devices therefore do not have to be converted; only little effort is required to assemble the direct current motor. The customer-specific connection geometry is implemented on the fully assembled DC motor by attaching a corresponding connection module. This results in a short lead time for customer-specific modifications. The direct current motor can be a brushed or also a brushless direct current motor.

The connection module is plugged onto the bearing through the bearing for the motor shaft of the DC motor, which is arranged on the end face of the motor housing and at least partially protrudes over the end face of the motor housing and forms the centering elevation. This enables the overall length of the engine to be shortened further. The connection module is only aligned with the DC motor bearing. An improved precision or tolerance is thus achieved.

The protruding rib of the connection module enables the DC motor to be attached very easily.

In yet another embodiment, it can be provided that the connection module in the assembled state is arranged in a precise angular position to the electrical connections of the direct current motor. This is especially important with brushed DC motors. The connection module is placed on the fully assembled motor on which the commutation has already been set. The angular position of the electrical connections of the motor is therefore already determined when the connection module is installed. Since the connection module is freely rotatable in the assembled state and can be rotated into any position, the electrical connections can therefore be brought into the desired position with respect to the attachment of the DC motor, ie with respect to the connection module. It is therefore possible to make good use of the installation space in which the direct current motors are installed. The DC motors can be installed close together, as the position of the connections is known.

It can also be provided that the connection module has a connection drilling pattern for connection to a connection point. This enables the direct current motor to be easily fastened at the desired position by means of screwing.

Fig. 1

Explosionsdarstellung des Gleichstrommotors,

Fig. 2

Ansicht des Gleichstrommotors von vorne, und

Fig. 3

Schnitt durch die Vorderseite des Motorgehäuses des Gleichstrommotors mit dem daran angebrachten Anschlussmodul.

In the following, embodiments of the invention are explained in more detail with reference to drawings. Show it:

Fig. 1

Exploded view of the DC motor,

Fig. 2

Front view of the DC motor, and

Fig. 3

Section through the front of the motor housing of the DC motor with the connection module attached.

Fig. 1 shows an exploded view of the direct current motor 1. The direct current motor can be designed as a brushed direct current motor or a brushless direct current motor. In the case shown, it is a brushed DC motor. The direct current motor 1 comprises a motor housing 3 and the connection module 2. The motor housing 3 is preferably cup-shaped. In other words, the motor housing 3 comprises a jacket surface 4 which is integrally connected to a motor housing base 5. A bearing seat 6 is formed in the motor housing base 5. In the bearing seat 6, a bearing 7 is arranged, in which one end of the motor shaft 8 is supported.

The motor housing base 5 thus forms an end face of the motor housing 3. The motor housing 3 is open on the end face of the direct current motor 1 opposite the motor housing base 5. A brush cover 9 with electrical connections 10 attached to it is fastened there.

The bearing seat 6 on the front side or on the motor housing base 5 of the motor housing 3 of the DC motor 1 is accessible from the outside and is designed so that its height is less than the height of the bearing 7 which is mounted in the bearing seat 6. The bearing 7 thus projects outwardly beyond the motor housing base 5 and forms a centering elevation. The motor housing base 5 is very simple except for the bearing seat 6 and has in particular, no connection bores for attaching the DC motor 1 to a connection point.

The connection module 2 has a centering recess on its rear side. The centering recess is approximately circular, the outer diameter of the centering recess being slightly larger than the outer diameter of the bearing 7. The connection module 2 is pushed onto the motor housing 3 of the direct current motor 1 coaxially to the motor shaft 8. The bearing 7 is then arranged in the centering recess of the connection module 2 and thus centers the connection module 2 on the motor housing 3. Since the diameter of the centering recess of the connection module 2 is slightly larger than the outer diameter of the bearing 7, the connection module 7 is after being plugged onto the Motor housing 3 can still be rotated.

On its front side 11 facing away from the motor housing base 5, the connection module 2 has fastening options for fastening the DC motor 1 at the desired installation location, e.g. in a car. In the case shown, holes 12 are provided for this purpose. The drilling pattern formed by the bores 12 corresponds to the customer-specific requirements. The position of the holes 12 is thus determined according to customer requirements. It is also possible to use other fastening options, e.g. Fastening ribs to be provided.

The connection module 12 is firmly connected to the motor housing 3 of the direct current motor 1. For example, the connection module 2 can be connected to the motor housing 3 by welding, gluing, pressing or shrinking.

Fig. 2 shows the DC motor 1 with the connection module 2 attached to it Fig. 1 from the front. The connection module 3 has three bores 12, by means of which the direct current motor 1 can be attached to the desired installation location, for example in a motor vehicle. The connection module 2, like the motor housing 3 of the DC motor 1, has a round cross-section, but can also have a square, triangular or oval shape with bores outside the motor diameter, which also allow fastening from the rear, under installation conditions in which the front is not accessible is. In the center, the connection module 2 has a bore 13 which serves as a passage for the motor shaft 8. The diameter of the bore 13 is larger than the diameter of the motor shaft 8, so that the bearing 7 can also be seen. On the rear of the connection module 2, this bore 13 is enlarged in diameter and forms the centering receptacle which is pushed onto the bearing 7. The connection module 7 is in a precise angular position with respect to the electrical connections 10 of the direct current motor 1 on the motor housing 3 mounted. The angle α between the bores 12 and the electrical connections 10 can be set with an accuracy of approximately ± 2 °.

Fig. 3 shows a cross section through the front of the motor housing 3, ie the motor housing base 5, with the connection module 2 attached. The bearing seat 6 is formed in the center of the motor housing base 5. In the bearing seat 6, the bearing 7 for the motor shaft is attached. The motor shaft is in Fig. 3 not shown. The height H1 of the bearing seat 6 is less than the height H2 of the bearing 7. The bearing 7 therefore protrudes beyond the motor housing base 5 to the outside. The bearing 7 thus forms a centering elevation. In order to enable a good hold of the bearing 7 in the motor housing 3, the height H1 of the bearing seat 6 should correspond to at least half the height H2 of the bearing 7. So H1 ≥ 0.5 applies. H2. However, the height H1 of the bearing seat 6 should not be too great either, so that the bearing 7 also creates a centering elevation on the end face of the motor housing base 5. The height H1 of the bearing seat 6 is therefore preferably in a range of approximately 2/3 to 4/5 of the height H2 of the bearing.

The connection module 2 has a central bore 13. The bore 13 is formed in sections. This means that the bore 13 is characterized by two areas with different diameters along its length. In the area facing the rear of the connection module 2, the bore 13 has a diameter D2. This diameter D2 corresponds approximately to the diameter of the bearing 7. In this area, the bore 13 is designed as a centering recess. The connection module 2 is plugged onto the motor housing 3 so that the area with the diameter D2 of the bore 13 is plugged onto the bearing 7. In the area facing the front side of the connection module 2, the diameter D1 of the bore 13 is smaller. A stop for the bearing 7 is thus formed here. The diameter D1 is sufficiently large so that the motor shaft of the DC motor 2 can exit to the outside.

The fastening bores 12 are also formed in the connection module 2. As already described, both the motor housing 3 and the connection module 2 are essentially circular in diameter. At its outer end, the motor housing base 5, a small shoulder 15 is formed in the motor housing 3. The diameter of the motor housing 3 in this area is therefore smaller than the diameter of the motor housing 3 in the central area. The connection module 2 has a protruding rib 14 on its circumference, the inside diameter of the rib 14 being slightly larger than the outside diameter of the tapered point 15 of the motor housing base 5. The rib 14 of the connection module 2 therefore comes to the tapered area 15 of the motor housing base 5 so that additional centering and stabilization of the connection module 2 on the motor housing 3 is achieved.

The assembly of the connection module 2 on the motor housing 3 of the direct current motor 1 is briefly explained below with reference to the drawings. First, the DC motor 1 is assembled. Since the DC motor shown is a brushed DC motor, the brush cover 9 with the electrical connections 10 attached is placed on the motor housing 3 of the DC motor 1 to complete the assembly of the DC motor 1. To set the commutation of the direct current motor 1, the brush cover is rotated relative to the stator arranged in the motor housing 3 with the magnets mounted in the stator. The brush cover 9 is then fixed in the desired position, so that the position of the electrical connections 10 of the direct current motor 1 is determined. The bearing 7 is inserted into the bearing seat 6 of the motor housing 3 and protrudes beyond the motor housing base 5 to the outside.

Subsequently, the connection module 2 is plugged onto the end face of the direct current motor 1 formed by the motor housing base 5. The motor shaft 8 is guided through the bore 13 which is formed in the center of the connection module 2. On the back of the connection module 2, the bore 13 is enlarged in diameter and forms a centering recess with the diameter D2. The diameter D2 of the centering recess is somewhat larger than the outer diameter of the bearing 7. As already described, the bearing 7 projects beyond the end face of the direct current motor 1. This is due to the fact that the height H1 of the bearing seat 6, which is formed in the end face or the motor housing base 5, is less than the height H2 of the bearing 7. The connection module is formed by the bearing 7 and the centering recess on the rear side of the connection module 2 2 centered on the DC motor 1. The connection module 2 is plugged onto the motor 1 until the rear of the connection module 2 rests on the motor housing base 5. The connection module is still in the assembly state. Since the diameter of the centering recess of the connection module 2 is slightly larger than the outer diameter of the bearing 7, the connection module 2 can still be rotated freely in the assembled state and thus brought into any position.

The connection module 2 is now rotated until the bores 12 or other fastening options formed on the connection module 2, for example a fastening rib, have the desired angular position relative to the electrical connections 10 of the direct current motor 1 or to the fastening points at the installation point of the direct current motor. If the connection module 2 is in the desired position, the connection module 2 is firmly connected to the motor housing 3. For example, the connection module 2 with the motor housing 3 can be welded, glued, pressed on or shrunk on. Motor housing 3 and connection module 2 are thus in the assembled state.

The total length of the direct current motor 1 with the motor housing 3 and the connection module 2 attached to it corresponds approximately to the length that the previously known small direct current motors without an additional adapter plate also have.

Claims (5)

1. A DC motor (1) comprising a motor housing (3) and at least one connection module (2) adapted to be installed on the motor housing (3), the connection module having fastening options for fastening the DC motor to an installation place, wherein the motor housing (3) comprises a front-sided centering elevation which cooperates with a centering recess on the connection module (2), characterized in that the connection module (2) is freely rotatable into any desired position in a mounting state on the motor housing (3) and is non-rotatably connected to the motor housing (3) in this desired position in the mounted state, wherein a bearing (7) for the motor shaft (8) of the DC motor (1) is arranged on the front side (5) of the motor housing (3), projects at least in part beyond the front side (5) of the motor housing (3) and forms the centering elevation, wherein the connection module (2) is attached to the bearing (7), and that the motor housing (3) comprises a motor housing bottom (5) with a shoulder (15) formed therein, and the connection module (2) has a projecting rib (14) which comes to rest in the shoulder (15).
2. The DC motor according to claim 1, characterized in that the front side (5) of the motor housing (3) has formed thereon a bearing seat (6) which is accessible from the outside and has arranged therein the bearing (7), the height of the bearing seat (6) being smaller than the height of the bearing (7).
3. The DC motor according to at least one of claims 1 or 2, characterized in that the connection module (2) is connected by gluing, welding or a forming process to the motor housing (3).
4. The DC motor according to at least one of claims 1 to 3, characterized in that the connection module (2) in the mounted state is arranged in a precise angular position relative to the electrical connections (10) of the DC motor (1).
5. The DC motor according to at least one of claims 1 to 4, characterized in that the connection module (2) has a connection drill pattern (12) for connection to a connection point.

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